In MN that does not include romantic partners. 

I’m currently stationed close to Venice with the US Army and am eyeing investing into Italy’s most romantic city.

I would reject because one has no income, but you can't do that in California if the other has enough to cover the rent.Students don't have jobs, but they have income from somewhere, otherwise, they couldn't be going to school.See about a parent co-signer for the student.First time living together in a romantic relationship is pretty iffy.

I can't even begin to imagine the trouble that landlords get into that start treating their tenants like friends or, worse, romantic relationships.

Hi Jean,Stock it with fish and have fun fishing all summer.Plant wild rice and maybe Ducks will show up--beautiful creatures to watch, and some people hunt them.Build a dock and toss in a small row boat....for romantic evening rides and something for the kids to play with.[1]>>> Have it tested for chemicals...some of these ponds have a years of farm runoff in them--pesticides and manure--it would be a shame if it's toxic.[2]>>> See if the sides go straight down (like a farmer scraped it out for whatever reason) and it would be dangerous vs. like a beach.Good Luck!

What are some solutions or ideas for new investors who have a romantic partner/spouse who does not like the idea of living in a duplex or having an ADU etc.

Don't sacrifice your time with your kids or your romantic time with your wife.

A relationship with a lender (not the romantic kind!).

That's a very romantic saying...but totally unrealistic.You're right about it being a numbers game, and the numbers with $ in front rule the game. 

It's romantic in a way, but also scares the tar out of people.